Brønsted Acid Catalyzed Dearomatization by Intramolecular Hydroalkoxylation/Claisen Rearrangement: Diastereo‐ and Enantioselective Synthesis of Spirolactams
作者:Peng‐Fei Chen、Bo Zhou、Peng Wu、Binju Wang、Long‐Wu Ye
DOI:10.1002/anie.202113464
日期:2021.12.20
A Brønstedacidcatalyzedintramolecular hydroalkoxylation/Claisen rearrangement is disclosed that involves an unexpected dearomatization of nonactivated arenes and heteroaromatic compounds and allows the practical and atom-economic synthesis of various valuable spirolactams. Moreover, the asymmetric version of this tandem cyclization is also achieved via kinetic resolution by chiral phosphoric acid
Synthesis of Cyclopropanoids via Substrate-Based Cyclization Pathways
作者:Uttam K. Mishra、Kaushalendra Patel、S. S. V. Ramasastry
DOI:10.1021/acs.orglett.8b03537
日期:2019.1.4
unexpected reactions triggered by the dimethyloxosulfonium methylide led to the discovery of unconventional approaches for the synthesis of cyclopropa-fused tetralones and indeno-spirocyclopropanes. These highly functionalized structures were further elaborated in one step to privileged scaffolds such as tetralones, indenones, and fluorenones. As a whole, the results presented herein establish new diversity-oriented
Annulative Morita–Baylis–Hillman reaction to synthesise chiral dibenzocycloheptanes
作者:Atanu Mondal、Shivangi、Pinku Tung、Siddhant V. Wagulde、S. S. V. Ramasastry
DOI:10.1039/d1cc02765d
日期:——
We describe the first metal-free and organocatalytic strategy to accesshighlyfunctionalised dibenzocycloheptanes via a phosphine-promoted annulative Morita–Baylis–Hillman (MBH) reaction. The method is manipulated to access to chiral dibenzocycloheptanes as well. This work represents a rare entry for the construction of seven-membered carbocycles via the MBH route. The realisation of several bioactive
A new method employing iron(III) acetylacetonate along with visible light is described to effect oxidative ring opening of cyclic ethers and acetals with unparalleled efficiency. The method allows for a photocatalytic radical chemistry approach to functionalize relatively inert cyclic ethers into useful synthetic intermediates. The methodology sheds further light on the use of underexplored iron complexes
Phosphine-Catalyzed Intramolecular Vinylogous Aldol Reaction of α-Substituted Enones
作者:Atanu Mondal、Bishnupada Satpathi、S. S. V. Ramasastry
DOI:10.1021/acs.orglett.1c03913
日期:2022.1.14
We demonstrate the first phosphine-catalyzed intramolecular vinylogous aldol reaction (IVAR) of α-substituted enones. This strategy provides access to various pentannulated (hetero)arenes and dibenzocycloheptanones incorporated with two contiguous stereocenters, one of which is an all-carbon quaternary center. The scope of this work is further broadened through elaborations of the IVAR adducts to (i)
我们展示了α-取代烯酮的第一个膦催化的分子内乙烯醇醛醇反应 (IVAR)。该策略提供了获得与两个连续立体中心结合的各种戊环化(杂)芳烃和二苯并环庚酮的途径,其中一个是全碳四元中心。这项工作的范围通过将 IVAR 加合物进一步扩大到 (i) 苯环化九元碳环系统,(ii) 有趣的 1,3-二烯、1,3,5-三烯和 1-yn- 3,5-二烯,和 (iii) 棘内酯 D 和 russujaponol F 的类似物。